Piston for internal-combustion engines



lam E6, 12923. LMiZl@ J. F. GUHJERA RlsToN F`oR INTERNAL CoMBUsTmN ENexNEs.

FILED JUNE 2l. '1920.

Patented dan. 16., 1923.

lTD STATES JOHN F. GUIDlER, OF BUFFALO, NEW YORK.

PISTON FOR INTERNAL-COMBUSTION ENGINES.

Application led June 21, 1920.

To all whom z5 may concer-a:

Be it known that I, JOHN F. GUIDER, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented a new and useful Improvement in Pistons for Internal- Combustion Engines, of which the following is a specification.

This invention relates to improvements in pistons for internal combustion engines and has for its object to produce a piston of practical, simple, strong and durable construction, whereby the objectionable noise due to side thrust of the piston in the cylinder, commonly known as piston slap, is eliminated, and also the scoring of the cylinder walls, which is frequently experienced with the common types of pistons when they are fitted sutciently close in an endeavor to eliminate the piston slap, and which scoring is due to unequal expansion of the piston and cylinder, and undue heating of the hearing portions at the sides of the piston are prevented.

lt `is well known that in the operation of internal combustion engines the pressure on the piston when the connecting rod or pitman is in a position at an inclination to the longitudinal axis of the cylinder, produces a side thrust on the piston in a direction at right angles to the axis of the wrist pin which connects 'the pitman to the piston. This causes the side slap or noise and consequent wear on the sidesV of the piston and cylinder which are lo cated at opposite sides of the axial plane of the wrist pin. Various means heretofore proposed to prevent this slap a-re objectionable or impractical from one or another standpoint. In some cases they add materially to the complication and cost of construction of the piston, and in others they weaken the piston s0 that `it is liable tobreakage, and its durability and reliability areV materially lessened.

In accordance with this invention the piston which is hollow, is provided preferably at each of the sides thereof which are at opposite sides of the axial plane of the wrist pin, with spaced, narrow slits which form between them a resilient or yielding wall portion which projects outwardly slightly beyond the adjacent7 outer surface portions of the piston so as to,

piston Serial No. 390,407.

engage the adjacent side of the internal surface of the cylinder and cushion the blow of the piston against the side of the cylinder.. Each `of these resilient projectn ing portions is connected at its opposite ends with the wall of the piston and is an integral portion of the piston wall, so that while the resilient portion is adapted to yield inwardly between its ends, it is not loose or detached at either end, and is therefore not liable to bebroken in the operation of the engine. The projecting resilient portion can be formed in different ways, for instance, either by grinding down the surface of the piston at opposite sides of the resilient portion so as to leave the latter projecting outwardly beyond the former, or by expanding the resilient portion of the wall between the slits by hammering or otherwise, to cause this portion to project slightly beyond the adjacent surface portions of the piston.

The projecting resilient portion or portions can be disposed in different positions and extend in different directions within the scope of this invention and several different arrangements are illustrated in the drawings.

ln the accompanying drawings:

Fig. l is a side elevation of a piston for internal combustion engines embodying the invention. V

Fig. 2 is a fragmentary longitudinal sectionalelevation thereof on line 2-2 Fig. l.

Fig. g3 is a side elevation of a slightly modified construction.

Figs. 4 and 5 are respectively similar side elevations of two other modifications of the invention.

Fig. 6 is an enlarged transverse section of the piston on line 6 6 Fig. 5.

Referringto the drawings, A represents the piston which, as usual, is in the form of a hollow shell having a closed upper or outer end and an open inner end, and is provided at opposite sides with hollow internal bearing bosses a for the wrist pin which extends dianietricallyi through the piston and connects the pitman to the piston. Z) Z) represent the usual piston rings retained in circumferential grooves in the piston near its outer end. The piston is preferably of the substantially cylindrical shape commonly employed, in which the outer end portion adjacent the piston rings is a few thousandths of an inch smaller in diameter than the inner end, so that the greater expansion of this end, which gets hottest, is possible, without causing the piston to bind in the cylinder.

In the construction shown in Figs, 1 and 2, the piston is provided in its side wall at one side of the plane of the bosses a for the wrist pin, with three parallel narrow slits 10 which ext-end lengthwise of the piston, thus forming two longitudinal wall portions 11, 11 which are separated at their side edges from each other and from the adjacent portions of the wall of the piston by die slits lO.` rllhe outer surfaces ot these portions 11 project outwardly slightly beyond, or are of slightly larger diameter than the outer surface of the adjacent wall portions 12 of the piston, so that they can contact with the adjacent side of the cylinder, while a slight clearance will be' left between the cylinder and the adjacent portions 12 of the piston. The portions 11 of the piston between the slits 10` are adapted to yield or spring inwardly under the lateral thrust to which the piston is subjected in the operation of the ingine, and thereby cushion the blow of the piston against Jthe side of the cylinder and prevent the noise which would otherwise result. The slits 10 do not extend to the ends of the piston and each of the portions 11 is therefore connected at both ends thereof integrally with the adjacent wall portions of the piston, and is .not in the nature of :1 spring tongue having a free or detached end. The outer surfaces of the portions 11 are concentric with the internal surface of the cylinder and the surface of the remaining portions 12 of the si de walls of the piston, and are preferably of substantially the same radius as the internal surface of the cylinder. This larger diameter of the surfaces of the portions 11 can be produced, as above explained, either by grinding down the remaining portions 12 of the wall of the piston or by expanding the portions 11 between the slits. tice, the diiference in diameter between the portions 11 and' 12 of the piston is very slight, only a few thousandths of an inch, and preferably the surfaces of the portions 11 are ground to leavela clearance of about oneA one-thousandth of an inch between them and the-internal surface of the cylinder.

Figs. 1 and 2 show the yielding parts 1.1 only at one side of the piston but the piston can be and preferably is made with the yielding'parts 11 at opposite sides thereof.

The construction shown in Fig. 3 is similar to that above explained, except that the piston is provided at each of its opposite sides with only twoslits 1S forming between Ythem a single yielding or resilient portion 14 which projects outwardly beyond the adjacent snrface portions of the piston and is ln pracsimilar in arrangement and function to the parts 1'1 above described.

1n the piston shown in Fig. e the slits 15 extend obliquely or helically. In this case, as in the other constructions described, the portion 16 of the wall between the slits projects outwardly beyond the remaining surface portions of the wall of the piston and is ofslightly largerdiameter than the same, so as to conform to the internal surface of the cylinder and bear against the same while leaving a clearance between the cylinder and the solid portions of the wall of the piston.

ln the construction shown in Figs. 5 and (3, the piston `is provided at each of the sides thereof at opposite sides of the wrist pin bosses, with two resilient or yielding portions 17 and 18 which extend circumferentially part way yaround the. piston, one preferably in the transverse plane of the wrist pin bosses and between the same, and the other near the inner end of thev piston. Each of these yielding or resilient portions is formed, as in the cases of the other pistons shown, by making spaced slits 19 in the wall of the piston and expanding the portions of the wall between the slits, or grinding down the remaining portions of the piston wall so as to leave theyielding or resilient portions slightly projecting. The second resilient portion 18 near the inner end of the piston can be dispensed with if preferred, and in some respects it is considered best to have only the one resilient part 1T located near the piston rings 7) and the transverse plane of the wrist pin bosses. lllhen only the one transverse resilient part 17 is' used, it should preferably be located at least as near the outer end of the piston as the wrist pin bosses. Otherwise it would not etfectually prevent the piston fromtipping on the wrist pin and its outer end slapping the side ot the cylinder. vIn all of the constructions described the projecting or resilient portions, regardless oftheir form or disposition on the piston, are formed by making spaced or parallel slits inthe wall ofthe-piston, and in each case the opposite ends of the resilient or yielding portion or portions are connected to the piston by integral portionsof the piston walls.

By slitting the wall of the piston and causing the parts between the slits to project outwardly beyond the adjacent surface portions of the piston, as explained, the parts between the slits are capable of springing or yielding sufiiciently to cushion the lateral. movements of the piston in the cylinder and prevent the slap or noise due to such move ments` but since the resilient parts are connected at both their ends with the piston, they are strong and durable and not liable to be broken. The projection of these parts is not so great that they have to be flexed to permit the piston to enter or move longitudinally in the cylinder and their pressure against the surface of the cylinder is not great enough to preclude proper lubrication. rlhe arrangement of the slits and resilient portion circumferentially of the piston in or near the transverse plane of the wrist pin bosses, as shown at 17 in Fig. 5, also has a marked beneficial cooling or heat insulating effect. They do not prevent the heat from being transmitted to the wrist pin bosses and adjacent parts of the piston where a relatively great bulli of its metal is disposed and where the heat is readily conducted off through the wrist pin and pitnian, but the slits impede heat transmission to and beyond the resilient parts 17, thus preventing undue expansion of the piston and reduction in the viscosity oiLl the lubricant at these points.

l claim as my invention:

l. A piston for internal combustion engines, comprising a hollow shell having a plurality of spaced slits in the side wall thereof, said slits providing integral yielding` portions in the side walls of said shell, said integral yielding portions projecting` uniformly outwardly slightly beyond adjacent surface portions oi the piston, a portion of at least one of said integral yielding portions extending into the transverse axial plane of the pivotal connection for the pitman of said piston. i

2. A piston for internal combustion engines, comprising a hollow shell having spaced slits in the side wall thereof at one side of the longitudinal axial plane of the pivotal connection for the pitman, the integral portion of the piston wall between said slits projecting outwardly slightly beyond and substantially concentric with the adjacent surface portions of the piston in the same transverse plane at opposite sides of said slits, said integral portion between said slits being connected at its opposite ends with the wall of the piston.

3. A piston for internal combustion engines, comprising a hollow shell having spaced parallel slits extending circumferentially through its side walls and part wa;7 around the same, the integral portion of the piston wall between said slits projecting outwardly at uniform inclinations from the ends of the slits, beyond the adjacent surface portions of the piston in the same transverse plane.

ll. A piston for internal combustion engines, comprising a hollow shell having spaced slits in the side wall thereof, said slits providing between them integral yielding portions in the side walls of said shell which have non-yielding adjacent piston sur- 'face portions in the same transverse plane, said integral yielding portions projecting outwardly slightly beyond said adjacent surface portions of the piston, and the outer sides oit' said yielding portions being concentric with said adjacent surface portions of the piston.

llfitness my hand this 18th day of June, 1920.

JHN l?. GUIDER.

Witnesses EDWARD F. HIMMELE, JOHN lVl. DUNDON. 

